Primary meningioma of the ethmoid sinus: a case report.

Meningioma is a well-recognized tumor of the central nervous system, but it rarely appears as a primary extracranial tumor of the paranasal sinuses. We report a case of a primary right anterior ethmoid meningioma that resembled a mucocele in its presentation. A primary meningioma can be differentiated from a secondary meningioma in three ways: (1) by observing an intact bony wall of the sinus on imaging or on inspection during surgery, (2) by noting the absence of a simultaneous intracranial meningioma on imaging or on inspection during surgery, and (3) by identifying a bulging of the sinus wall toward the cranium rather than in the opposite direction.